Use pivot point or 3d cursor as center when scaling down verts in edit mode in 2.8 instead of selected volume center
You need to set your pivot point to 3D cursor.
It's currently se to median.

Just click the pivot point menu, and select 3D cursor.  



Short explanation:
When you're in Object mode, having your pivot point set to an object's median is very useful.

But in Edit mode, vertices don't care where the object's median point is.
They calculate their own median.
That's why there's the 3D cursor - to set your pivot point easily.